我国部分地区禽病原性大肠杆菌的分离与鉴定

THE ISOLATION AND IDENTIFICATION OF PATHOGENIC ESCHERICHIA COLI ISOLATES OF CHICKEN ORIGIN FROM SOME REGIONS IN CHINA

从江苏、广东、河南、新疆、四川、北京、黑龙江等１８个省、市、自治区临诊上有典型大肠杆菌病病变的病禽１０５１羽采集病料，分离培养和鉴定出５９５株大肠杆菌。经Ｏ血清型测定，除１４４株未能定型、１１株自凝外，共鉴定出４４０个分离株的Ｏ血清型。这些分离株覆盖了６０个血清型，但以Ｏ１８、Ｏ７８、Ｏ２、Ｏ８８、Ｏ１１、Ｏ２６、Ｏ４、Ｏ１、Ｏ１２７和Ｏ１３１等１０个血清型为主，共２６４株，占定型菌株的６０％；前６种血清型在种类上只占定型菌株血清型总数的１０％，却拥有２０４个分离株，占定型菌株的４６３６％。因此，可以认定Ｏ１８、Ｏ７８、Ｏ２、Ｏ８８、Ｏ１１、Ｏ２６等６个血清型为优势血清型。不同地区优势血清型分离株６０个，以每分离株１０７菌落形成单位（ＣＦＵ）细菌气管内接种１日龄无特定病原体（ＳＰＦ）鸡６羽，根据接种后７天内发生死亡和病变鸡的比例，确定出高致病株、中度致病株和低致病株分别为８３３３％、１０％和６６７％；其它常见血清型Ｏ４、Ｏ１、Ｏ１２７和Ｏ１３１分离株３０个和１０个非常见血清型分离株，按同样方法接种１日龄易感鸡６羽，高致病株、中度致病株和低致病株分别为９０％、１０％和０％。结果表明：我们所收集的分离株均?

The purpose of this study was to characterize avian Escherichia coli isolates collected from 18 provinces in China 595 out of 703 strains were identified with Escherichia coli isolates in 10 biochemical reactions Among 595 E coli isolates,serogroups of 440 strains were determined while 144 were not serogroupable and 11 were self-agglutinated 60 serogroups were discovered in these isolates and 60 per cent out of which beloging to 10 O serogroups:O 18 ,O 78 ,O 2 ,O 88 ,O 11 ,O 26 ,O 4 ,O 1 ,O 127 and O 131 These O serogroups isolates were 262 in total;in which O 18 ,O 78 ,O 2 ,O 88 ,O 11 and O 26 isolates added up to 204,46 36% among the 440 serogroupable isolates,they were predominant serogroupes in this study The relative pathogenicity of 60 predominant serogroups Escherichia coli isolates from different regions was evaluated in specific-pathogen-free(SPF) day-old chickens Six birds per isolate were inoculated intratracheally with 0 1ml of a 24-hour Luria-Bertani(LB) broth culture containing 10 7 colony-forming units(CFU) of E coli Based on mortality and lesions occurring during a 7-day postinoculation period,83 33%,10% and 6 67% of 60 isolates were characterized as high,intermediate and low in pathogenicity,respectively;the pathogenicity of 30 other common serogroups isolates,which belonging to O 4 ,O 1 ,O 127 and O 131 ,and 10 of uncommon serogroups isolates were also evaluated by the same way in susceptible day-old chickens,90%,10% and 0% of these isolates were high,intermediate and low in pathogenicity These results suggested that all Escherichia coli isolates we collected were pathogenic,in which more than 83% strains were high pathogenic ones,less than 17% were intermediate to low in pathogenicity